JP2021162014A - Actuator - Google Patents

Abstract

To provide an actuator capable of achieving high output.SOLUTION: An actuator has a skeleton structure portion 12 forming a skeleton structure surrounding a housing portion 11, and a volume-changing portion 13 housed in the housing portion 11. The volume-changing portion 13 increases its volume when external energy is input. The skeleton structure portion 12 has a Young's modulus higher than that of the volume-changing portion 13. A shape of the housing portion 11 is an anisotropic shape having a maximum width LD2 of the housing portion 11 in one direction, longer than a maximum width LD3 of the housing portion 11 in the other direction different from one direction.SELECTED DRAWING: Figure 2

Description

The present invention relates to an actuator.

As an actuator using a material that converts external energy input from the outside other than mechanical energy into mechanical energy and outputs an external force, an actuator using a polymer fiber material is described in Patent Document 1 and Non-Patent. It is disclosed in Document 1. This actuator utilizes the operation of a polymer fiber material generated by the input of thermal energy. In the actuator disclosed in Patent Document 1, the fiber materials of PA6 and PA66 are used. In the actuator disclosed in Non-Patent Document 1, the fiber material of PA11 is used.

U.S. Pat. No. 9,784,249

2017 Spring Meeting of the Japan Precision Engineering Society Academic Lecture Proceedings, 171 and 172 pages, Japan Precision Engineering Society

By the way, an actuator having a higher output than a conventional actuator is required. In order to increase the output of the actuator, that is, to increase the external force and to make the actuator material more deformable, both the property of large strain generated by the input of external energy and the property of high Young's modulus are required. It is necessary to use the material to have.

In view of the above points, it is an object of the present invention to provide an actuator capable of increasing output.

According to the invention according to claim 1, in order to achieve the above object.
The actuator includes a skeletal structure part (12, 21, 22, 42) that forms a skeletal structure surrounding the housing part (11, 24, 41), and a volume changing part (13, 23, 43) housed in the housing part. Have,
The volume of the volume change part increases when external energy other than mechanical energy is input from the outside.
The skeletal structure has a higher Young's modulus than the volume change part,
When external energy is input to the volume change part, the volume of the volume change part increases, and due to the increase in the volume of the volume change part, the accommodating part contracts in one direction (D2, D11), and the accommodating part becomes another. The skeletal structure is deformed so as to spread in the direction (D3, D12).

According to this, the Young's modulus of the actuator can be increased as compared with the case where the actuator is composed of only the material constituting the volume change portion.

Further, according to this, the volume of the volume changing portion is increased by inputting external energy to the volume changing portion, and the accommodating portion is contracted in one direction due to the increase in the volume of the volume changing portion, so that the accommodating portion is compressed. The skeletal structure is deformed so as to spread in the other direction. As a result, the actuator generated when external energy is input is compared with the case where the actuator is composed only of the materials constituting the skeleton structure portion and the case where the actuator is composed only of the materials constituting the volume change portion. The strain can be increased.

In this way, it is possible to give the actuator both a property that the strain generated by the input of external energy is large and a property that the Young's modulus is high. Therefore, it is possible to increase the output of the actuator.

The reference reference numerals in parentheses attached to each component or the like indicate an example of the correspondence between the component or the like and the specific component or the like described in the embodiment described later.

It is a schematic diagram of the actuator in 1st Embodiment. It is a figure which shows the model of the unit structure of the actuator of FIG. It is a figure which shows the model of the bulk structure of the polyamide-based fiber material. It is an enlarged view of the IV part in FIG. 3, and is the figure which shows the model of the unit structure of the polyamide-based fiber material. It is a figure which shows the model of the unit structure of the polyamide-based fiber material, and is the figure which shows the shape change of the unit structure by the volume change of the amorphous part. It is a figure which shows the relationship between the magnitude of the tension applied to the fiber material of PA6, and the coefficient of linear expansion of the fiber material of PA6. It is a figure which shows the Young's modulus of each of the crystalline part and the amorphous part of PA6, and the Young's modulus of the fiber material of PA6. It is a figure which shows the model of the unit structure of the polyamide-based fiber material. It is a figure which shows the relationship between the crystallinity and the coefficient of linear expansion in PA6. It is a figure which shows the calculation result and the measured value of the linear expansion coefficient of the fiber material of PA6. It is a flowchart which shows the manufacturing method of the fiber material of PA12. It is a schematic diagram which shows the manufacturing apparatus of the fiber material of PA12. It is a figure which shows the measurement result of the shrinkage ratio of each fiber material of PA12, PA6, PA66 manufactured at the same draw ratio. It is a schematic diagram of the actuator which has a node in 2nd Embodiment. It is a schematic diagram of the actuator which does not have a node in 2nd Embodiment. It is a figure which shows the relationship between the expansion coefficient of a polymer material, and the contraction rate of an actuator in each of the actuator which has a knot part and the actuator which does not have a knot part in 2nd Embodiment. It is a figure for demonstrating the manufacturing method of the actuator in an Example. It is a figure for demonstrating the manufacturing method of the actuator following FIG. It is a figure for demonstrating the manufacturing method of the actuator following FIG. It is a photograph of the actuator before heating in an embodiment. It is a photograph of the actuator after heating in an example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the following embodiments, parts that are the same or equal to each other will be described with the same reference numerals.

(First Embodiment)
The actuator 1 shown in FIG. 1 uses a material that converts external energy input from the outside other than mechanical energy into mechanical energy and outputs it. Specifically, this actuator 1 uses a fiber material, and contracts in the fiber axial direction D1 of the fiber material by inputting external energy. As a result, the tensile force in the fiber axial direction D1 is output to the outside. The actuator 1 shown in FIG. 1 is linear, but may be coiled in order to increase the stroke.

Next, the material design of the actuator 1 found by the present inventors will be described.

The actuator 1 is made of a material having a plurality of unit structures 10. FIG. 2 shows the change in the unit structure before and after the input as a model diagram. The left side of FIG. 2 shows the state before input. The right side of FIG. 2 shows the state after input. As shown on the left side of FIG. 2, the unit structure 10 includes a skeletal structure portion 12 that forms a skeletal structure surrounding one housing portion 11, and a volume changing portion 13 housed in the one housing portion 11. That is, the actuator 1 has a skeleton structure portion 12 and a volume changing portion 13.

The skeleton structure portion 12 is a portion that mainly contributes to the strength of the material, and is a structural portion that forms the skeleton of the material. The Young's modulus of the skeletal structure portion 12 is higher than the Young's modulus of the volume change portion 13. The skeletal structure portion 12 has a three-dimensional structure. The skeletal structure portion 12 extends like a pantograph. A part of the extending direction of the skeletal structure portion 12 is inclined in a direction orthogonal to that direction.

The skeletal structure portion 12 preferably has a hollow shell structure, that is, a closed structure that completely covers the accommodating portion 11. The skeleton structure portion 12 does not have to have a closed structure. When the volume of the volume changing portion 13 accommodated in the accommodating portion 11 is increased, as the skeletal structure portion 12 receives a larger force, a part of the skeletal structure portion 12 is pushed and tilted by the force, which will be described later. The amount of deformation of the skeletal structure portion 12 can be increased.

Further, in the unit structure, the portions constituting the skeletal structure portion 12 are preferably chemically bonded and continuous, but may not be chemically bonded. In the material constituting the actuator 1, the plurality of skeletal structure portions 12 are three-dimensionally connected to each other. Each of the plurality of skeletal structure portions 12 is preferably chemically bonded to each other and continuous, but may not be chemically bonded to each other.

The volume change portion 13 is surrounded by the skeletal structure portion 12. The volume of the volume changing unit 13 is increased by inputting external energy other than mechanical energy from the outside. Examples of external energy include thermal energy, electrical energy, chemical energy, and light energy. For example, the input of thermal energy means that the temperature of the actuator is increased. When the volume increase due to the input of external energy is compared under the same conditions, the volume increase of the volume change portion 13 is larger than the volume increase of the skeleton structure portion 12.

The shape of the accommodating portion 11 is a shape having anisotropy in the direction of the maximum width of the accommodating portion 11 in each direction, that is, a shape other than a sphere. That is, the shape of the accommodating portion 11 is an anisotropic shape in which the maximum width LD2 of the accommodating portion 11 in one direction is longer than the maximum width LD3 of the accommodating portion 11 in the other direction different from the one direction. For example, as shown on the left side of FIG. 2, when the cross-sectional shape of the accommodating portion 11 is a prolate spheroid, the longitudinal direction D2 corresponds to one direction, and the lateral direction D3 perpendicular to the longitudinal direction corresponds to the other direction. Further, the longitudinal direction D2 is a direction along the fiber axis direction D1 of FIG.

As shown on the left side of FIG. 2, the state before the external energy is input is the state in which the volume changing portion 13 is accommodated in the accommodating portion 11 of the skeletal structure portion 12, and the shape of the accommodating portion 11 is a sphere. It is an anisotropic shape other than. The volume change unit 13 is arranged in advance so that the direction of expansion when energy is input is the lateral direction D3. When external energy is input to the skeleton structure portion 12 and the volume change portion 13, the volume change portion 13 expands in the lateral direction D3. The volume change portion 13 has a larger volume change amount due to the input of external energy than the skeleton structure portion 12. Therefore, the skeletal structure portion 12 is pushed in the lateral direction D3, expands, and contracts in the longitudinal direction D2.

Therefore, as shown on the right side of FIG. 2, the skeleton structure portion 12 is deformed in the direction in which the shape of the accommodating portion 11 approaches the sphere due to the increase in the volume of the volume changing portion 13. That is, as the volume of the volume changing portion 13 increases, the accommodating portion 11 contracts in the longitudinal direction D2, and the skeletal structure portion 12 deforms so that the accommodating portion 11 expands in the lateral direction D3. In other words, the volume changing portion 13 expands in a direction orthogonal to the fiber axial direction D1. A part of the skeleton structure portion 12 moves in a direction orthogonal to the fiber axis direction D1 in cooperation with the volume change portion 13 as the volume change portion 13 expands. The other part of the skeleton structure portion 12 moves in the direction of contracting the volume changing portion 13 in the fiber axial direction D1. In this way, the volume changing portion 13 does not expand isotropically, but contracts in one direction and expands in the other direction. That is, the volume change portion 13 has anisotropy.

By the way, in order to increase the output of the actuator 1, for example, when the actuator 1 exerts a tensile force on the outside of the actuator 1 so that the actuator 1 contracts more greatly, the strain generated by the input of external energy is large. It is necessary to use a material having both properties and properties with a high Young's modulus. However, in general, a material having a high Young's modulus has a small strain. On the other hand, a material having a large strain has a low Young's modulus. For this reason, conventionally, there has been no material having both properties.

On the other hand, by using the material having the unit structure 10 for the actuator 1, the Young's modulus of the actuator 1 is increased as compared with the case where the actuator 1 is composed only of the materials constituting the volume changing portion 13. Can be done.

Further, when the actuator 1 is composed of only the materials constituting the skeleton structure portion 12, the amount of volume change when external energy is input is small, and the strain (that is, the amount of deformation) generated in the actuator 1 is small. Further, when the actuator 1 is composed of only the materials constituting the volume changing portion 13, the actuator 1 expands isotropically when external energy is input, so that the strain generated in the actuator 1 is small.

On the other hand, in the material having the unit structure 10, the volume of the volume change unit 13 is increased by inputting external energy to the volume change unit 13. As the volume of the volume changing portion 13 increases, the skeletal structure portion 12 is deformed so that the accommodating portion 11 contracts in one direction and the accommodating portion 11 expands in the other direction. As a result, when external energy is input, as compared with the case where the actuator 1 is composed only of the materials constituting the skeleton structure portion 12 and the case where the actuator 1 is composed only of the materials constituting the volume changing portion 13. The strain of the actuator 1 generated in the above can be increased.

In this way, it is possible to give the actuator 1 both a property that the strain generated by the input of external energy is large and a property that the Young's modulus is high. Therefore, the output of the actuator 1 can be increased.

In the actuator 1, the contraction operation in one direction of the accommodating portion 11 can be used for the output of the actuator 1. However, the present invention is not limited to this, and the expansion operation of the accommodating portion 11 in the other direction can be used for the output of the actuator 1.

Next, the fiber material of PA12 (that is, polyamide 12) that embodies the above material design will be described. As will be described later, this fiber material is produced by stretching the fiber in the process of manufacturing the fiber material of PA12. PA12 is a polyamide-based crystalline polymer material having a crystalline portion and an amorphous portion. The polymer material is a polymer organic compound. In addition to PA12, the polyamide-based crystalline polymer material includes PA6 (that is, polyamide 6) and PA66 (that is, polyamide 66).

A fiber material composed of a polyamide-based crystalline polymer material produced by stretching fibers (hereinafter, this fiber material is referred to as a polyamide-based fiber material) has a bulk structure 20 shown in FIG.

Specifically, as shown in FIG. 3, the polyamide-based fiber material has a plurality of crystal portions 21, a plurality of tie molecules 22, and a plurality of amorphous portions 23. Each of the plurality of crystal portions 21 is a portion in which polymer chains are regularly arranged. Specifically, each of the plurality of crystal portions 21 is a lamella crystal portion. Each of the plurality of tie molecules 22 is a portion where a polymer chain extends so as to connect each of the plurality of crystal portions 21 to each other. The plurality of crystal portions 21 and the plurality of tie molecules 22 form a skeletal structure surrounding each of the plurality of accommodating portions 24. Each of the plurality of amorphous portions 23 is a portion in which polymer chains are irregularly arranged. Each of the plurality of amorphous portions 23 is accommodated in each of the plurality of accommodating portions 24. That is, each of the plurality of amorphous portions 23 is confined in a portion surrounded by the plurality of crystal portions 21 and the plurality of tie molecules 22.

The bulk structure 20 shown in FIG. 3 includes the unit structure 20A shown in FIG. 4, that is, the crystal portion 21, the tie molecule 22, and the amorphous portion 23. As shown in FIG. 4, the plurality of crystal portions 21 and the plurality of tie molecules 22 form a skeletal structure surrounding one accommodating portion 24. One of the plurality of amorphous portions 23 is accommodated in the one amorphous portion 24. Therefore, one of the plurality of amorphous portions 23, the amorphous portion 23, corresponds to the volume changing portion 13 of the unit structure 10 of FIG. Of the plurality of crystal portions 21 and the plurality of tie molecules 22, the portion surrounding one of the volume changing portions 13 corresponds to the skeletal structure portion 12 of the unit structure 10 of FIG.

The first direction D2 and the second direction D3 in FIGS. 3 and 4 are orthogonal to each other. The first direction D2 is a direction along the fiber axial direction D1. The unit structure 20A adjacent to the second direction D3 is provided so that the position of the first direction D2 is deviated.

That is, as shown in FIG. 3, the plurality of tie molecules 22 include a plurality of first tie molecules 221 extending in the first direction D2 and a plurality of second tie molecules 222 extending in the first direction D2. Each of the plurality of first tie molecules 221 and each of the plurality of second tie molecules 222 are alternately provided in the second direction D3.

One of the second tie molecules 222 of the plurality of second tie molecules 222 and one of the first tie molecules 221 of the plurality of first tie molecules 221 on one side of the second direction D3 with respect to the second tie molecule 222. A first space B1 is formed between the first tie molecule 221a located next to it. Further, one second of the one second tie molecule 222 and the plurality of first tie molecules 221 located next to the other side of the second direction D3 with respect to the one second tie molecule 222. A second space B2 is formed between the tie molecule 221b and the tie molecule 221b.

The plurality of crystal portions 21 include a plurality of first crystal portions 21a provided in the first space B1. The plurality of amorphous portions 23 include a plurality of first amorphous portions 23a provided in the first space B1. Each of the plurality of first crystal portions 21a and each of the plurality of first amorphous portions 23a are alternately provided in the first direction D2 in the first space B1.

Further, the plurality of crystal portions 21 include a plurality of second crystal portions 21b provided in the second space B2. The plurality of amorphous portions 23 include a plurality of second amorphous portions 23b provided in the second space B2. Each of the plurality of second crystal portions 21b and each of the plurality of second amorphous portions 23b are alternately provided in the first direction D2 in the second space B2.

One of the plurality of first crystal portions 21a of the first space B1 has the first crystal portion 21a with respect to the second amorphous portion 23b of one of the plurality of second amorphous portions 23b of the second space B2. They face each other in the second direction D3. That is, when one first crystal portion 21a is projected onto one second amorphous portion 23b in the second direction D3, one projected first crystal portion 21a is projected onto one second amorphous portion 23b. Overlap. Further, one of the plurality of second crystal portions 21b of the second space B2 has a second crystal portion 21b with respect to one of the plurality of first amorphous portions 23a of the first space B1 with respect to the first amorphous portion 23a. Therefore, they face each other in the second direction D3. That is, when one second crystal portion 21b is projected onto one first amorphous portion 23a in the second direction D3, one projected second crystal portion 21b is projected onto one first amorphous portion 23a. Overlap.

As described above, the position of the first crystal portion 21a of the plurality of first crystal portions 21a in the first direction D2 and the first direction of the second crystal portion 21b of the plurality of second crystal portions 21b. It is different from the position at D2. The position of one of the first amorphous portions 23a in the first direction D2 and the first direction of the second amorphous portion 23b of the plurality of second amorphous portions 23b. It is different from the position at D2. That is, the second crystal portion 21b is provided at the position of the second space B2 which is the same as the position of the first amorphous portion 23a of the first space B1 in the first direction D2.

The length of each of the plurality of amorphous portions 23 in the first direction D2 is longer than the length of each of the plurality of crystal portions 21 in the first direction D2. Therefore, each of the plurality of tie molecules 22 is located between the first crystal portion 21a and the second crystal portion 21b, which have the shortest positional relationship in the first direction D2 among the plurality of crystal portions 21. It is a portion and includes a crystal connecting portion 22A that connects the first crystal portion 21a and the second crystal portion 21b. The crystal connecting portion 22A is adjacent to both the first amorphous portion 23a and the second amorphous portion 23b in the second direction D3. The crystal connecting portion 22A is inclined with respect to the first direction D2, but may be parallel to the first direction D2.

At the time of volume expansion of the amorphous portion 23, the outer peripheral surface of the amorphous portion 23 expanded in the second direction D3 pushes the inner peripheral surface of the tie molecule 22 in the same direction as the expansion direction. The expansion direction is the second direction D3. With the deformation of the pressed tie molecule 22, the crystalline portion 21 forming the skeleton structure together with the tie molecule 22 pushes the amorphous portion 23 in the first direction D2, so that the amorphous portion 23 contracts in the first direction D2. Each is arranged so that it does.

As shown in FIG. 4, looking at the cross section of the bulk structure 20 cut so as to include the stretching direction of the tie molecule 22, the cross-sectional shape of one accommodating portion 24 is octagonal. In one accommodating portion 24, the maximum width LD2 of the accommodating portion 24 in the first direction D2 is longer than the maximum width LD3 of the accommodating portion 24 in the second direction D3. The first direction D2 is the longitudinal direction of one housing portion 24. The first direction D2 corresponds to one direction of the accommodating portion 11 in FIG. The second direction D3 is the lateral direction of one accommodating portion 24. The second direction D3 corresponds to the other direction of the accommodating portion 11 in FIG.

The amorphous portion 23 is formed of randomly entwined polymer chains. This polymer chain extends in the first direction D2 as a whole. That is, the stretching direction of the polymer chain of the amorphous portion 23 is along the fiber axial direction D1. Therefore, when the total volume of each of the plurality of amorphous portions 23 increases, each of the plurality of amorphous portions 23 contracts in the first direction D2, so that the actuator 1 having the bulk structure 20 contracts in the fiber axial direction D1. Shrinks to.

When the actuator 1 is heated and heat energy is input to the amorphous portion 23, the total volume of the amorphous portion 23 increases. When the actuator 1 is cooled and heat energy is released from the amorphous portion 23, the total volume of the amorphous portion 23 is reduced. That is, the heat input and the volume change are reversible.

It will be described that the actuator 1 contracts in the fiber axial direction D1 by heating. The left side of FIG. 5 shows the unit structure 20A when the volume of the amorphous portion 23 is small. That is, the left side of FIG. 5 shows the unit structure 20A in a state where the actuator 1 is not heated. This state is a natural state in which the amorphous portion 23 does not expand in volume. In this state, the tie molecule 22 in contact with the amorphous portion 23 is not subjected to a force that moves in the expansion direction. Therefore, the angle φ _t1 of the tie molecule 22 is small. Here, as shown in FIG. 4, the length of the outer side of the crystal connecting portion 22A of the tie molecule 22 is L. At this time, the length of the crystal connecting portion 22A of the tie molecule 22 in the first direction D2 is Lcosφ _t1 .

The right side of FIG. 5 shows the unit structure 20A when the volume of the amorphous portion 23 is large. At this time, the pressed tie molecule 22 is deformed as the amorphous portion 23 expands, so that the angle φ _t2 of the tie molecule 22 is large. At this time, the length of the crystal connecting portion 22A of the tie molecule 22 in the first direction D2 is Lcosφ _t2 . _{The angles φ t1} and φ _t2 of the tie molecule are angles formed by the crystal connecting portion 22A with respect to the first direction D2.

As the total volume of the amorphous portion 23 increases, the unit structure 20A changes from the shape on the left side of FIG. 5 to the shape on the right side of FIG. Then, the length of the crystal connecting portion 22A of the tie molecule 22 in the first direction D2 decreases from Lcosφ _{t1 to Lcosφ t2.} That is, as shown on the right side of FIG. 5, the amorphous portion 23 contracts in the first direction D2 and expands in the second direction D3. In other words, the skeletal structure composed of the crystal portion 21 and the tie molecule 22 is deformed so that the accommodating portion 24 contracts in the first direction D2 and the accommodating portion 24 expands in the other direction. The first direction D2 corresponds to one direction, and the second direction D3 corresponds to the other direction. In this way, the unit structure 20A imparts anisotropy to the volume change of the amorphous portion 23.

Further, when the total volume of the amorphous portion 23 decreases, the unit structure 20A changes from the shape on the right side of FIG. 5 to the shape on the left side of FIG.

It is known that a fiber material composed of a general crystalline polymer material has a structure in which crystalline portions and amorphous portions are alternately connected. Further, it is generally considered that the heat shrinkage of the fiber material composed of the crystalline polymer material is due to the entropy elasticity of the amorphous portion.

However, in polyamide-based fiber materials, a phenomenon due to entropy elasticity may not be observed. Specifically, as shown in FIG. 6, the amount of shrinkage (that is, the linear expansion coefficient) does not increase when tension is applied to the polyamide-based fiber material in the fiber axial direction, and as shown in FIG. 7, it is amorphous. It can be mentioned that the Young's modulus of the part and the Young's modulus of the fiber material are significantly different. The circles in FIG. 6 indicate the measured values of the coefficient of linear expansion. The straight line shown by the broken line in FIG. 6 shows the expected coefficient of linear expansion due to the entropy elasticity. The diameter of the sample used in the measurement of FIG. 6 is 0.37 mm.

Considering that the shrinkage of the polyamide-based fiber material is caused by the unit structure 20A shown in FIG. 4, in which anisotropy is imparted to the volume change of the amorphous portion 23, no phenomenon due to entropy elasticity is observed. Can explain that. _{That is, as shown in FIG. 5, the angles φ t1} and φ _t2 of the tie molecule 22 change due to the volume change of the included amorphous portion 23, so that anisotropy appears in the volume change of the bulk structure 20. In this case, the shrinkage of the polyamide-based fibrous material is caused by the expansion of the free volume rather than the entropy elasticity. Therefore, as shown in FIG. 6, the amount of shrinkage of the fiber material at the time of applying tension does not change even if the magnitude of the applied tension is different. Further, the Young's modulus of the polyamide-based fiber material depends on the Young's modulus of the tie molecule 22 instead of the amorphous portion 23. Therefore, as shown in FIG. 7, the Young's modulus of the fiber material of PA6 shows a value between the Young's modulus of the crystalline portion 21 and the Young's modulus of the amorphous portion 23.

Next, the rationale for the polyamide-based fiber material having the unit structure 20A will be described. The fact that the polyamide-based fiber material has a unit structure of 20A means that the calculated coefficient of linear expansion of the polyamide-based fiber material by the geometric calculation of the unit structure 20A is the same as the measured value of the coefficient of linear expansion of the polyamide-based fiber material. It is proved from the fact that it is close to or close to it.

The coefficient of linear expansion of the polyamide-based fiber material is calculated using the formulas shown in Equations 1, 2, and 3 below. The equations of Equation 1, Equation 2, and Equation 3 are derived by analysis based on the model of the unit structure 20A.

数１の式において、ΔＬ_１／（Ｌ_１ΔＴ）は、第１方向Ｄ２での線膨張係数である。数１の式中の各記号は、図８に示す単位構造２０Ａの各構成要素の寸法または角度である。Ｌ_１は、単位構造２０Ａの一部の第１方向Ｄ２での長さである。ΔＬ_１は、Ｌ_１の変化量である。ΔＴは、温度変化量である。Ｌ_ｔは、タイ分子２２の結晶連結部２２Ａの長さである。φ_ｔは、タイ分子２２の角度であり、結晶連結部２２Ａが第１方向Ｄ２に対してなす角度である。α_ａは、非晶部２３の線膨張係数である。Ｌ_ｃは、結晶部２１の第１方向Ｄ２での長さである。Ｌ_Ｗは、結晶部２１の第２方向Ｄ３での長さである。また、数１の式中のＬ_Ｗ／Ｌ_ｔの逆数は、下記の数２に示す式で表される。

In the equation of Equation 1, ΔL ₁ / (L ₁ ΔT) is the coefficient of linear expansion in the first direction D2. Each symbol in the equation of Equation 1 is the dimension or angle of each component of the unit structure 20A shown in FIG. L ₁ is the length of a part of the unit structure 20A in the first direction D2. ΔL ₁ is the amount of change _{in L 1.} ΔT is the amount of temperature change. L _t is the length of the crystal connecting portion 22A of the tie molecule 22. φ _t is the angle of the tie molecule 22, and is the angle formed by the crystal connecting portion 22A with respect to the first direction D2. α _a is the coefficient of linear expansion of the amorphous portion 23. L _c is the length of the crystal portion 21 in the first direction D2. L _W is the length of the crystal portion 21 in the second direction D3. The reciprocal of L _W / L _{t in} the equation of Equation 1 is represented by the equation shown in Equation 2 below.

数２の式において、Ｌ_ｃ／Ｌ_Ｗは、結晶部２１のアスペクト比である。Ｘ_ｃは、ポリアミドの結晶化度である。また、数１の式中のＬ_ｃ／Ｌ_ｔは、下記の数３に示すように、結晶部２１のアスペクト比と数２の式の逆数の値との積である。

In the equation of Equation 2, L _c / L _W is the aspect ratio of the crystal portion 21. X _c is the crystallinity of the polyamide. _{Further, L c} / L _{t in} the equation of Equation 1 is the product of the aspect ratio of the crystal portion 21 and the value of the reciprocal of the equation of Equation 2 as shown in Equation 3 below.

数１、数２、数３に示す式を用いた線膨張係数の理論計算に必要なパラメータは、非晶部２３の線膨張係数α_ａ、タイ分子２２の角度φ_ｔ、結晶部２１のアスペクト比（Ｌ_ｃ／Ｌ_Ｗ）、結晶化度Ｘ_ｃの４つである。

The parameters required for the theoretical calculation of the linear expansion coefficient using the equations shown in Equations 1, 2, and 3 are the linear expansion coefficient α _{a of the amorphous portion 23, the angle φ t} of the tie molecule 22, and the aspect of the crystal portion 21. The ratio (L _c / L _W ) and the crystallinity X _c are four.

As shown in FIG. 9, the coefficient of linear expansion α _a of the amorphous portion 23 is obtained by extrapolating from the relationship between the degree of crystallinity and the coefficient of linear expansion. In FIG. 9, the measured values of the linear expansion coefficients of PA6 having different crystallinities are plotted. From these plots, the relationship between the crystallinity and the coefficient of linear expansion can be obtained. From this relationship, the coefficient of linear expansion when the crystallinity is 0% is calculated. The calculated coefficient of linear expansion of the amorphous portion 23 of PA6 was 2.064 × 10 ^-4 / K.

The angle φ _t of the tie molecule 22 is obtained from the measurement result by small-angle X-ray scattering. Angle phi _t of tie molecules 22 of the PA6 was less than 30 degrees.

The aspect ratio of the crystal portion 21 is obtained from the measurement result by wide-angle X-ray scattering. The aspect ratio of the crystal portion 21 of PA6 was 1.83.

The crystallinity _Xc is determined from the measurement result by DSC (that is, differential scanning calorimetry). _{Specifically, the degree of crystallization Xc} can be obtained by using the following formula for calculating the degree of crystallization, the measured value of the amount of heat of fusion, and the amount of heat of fusion of a 100% crystal. A measured value or a literature value is used as the amount of heat of fusion of the 100% crystal.

Crystallinity = (measured value of heat of fusion / 100% heat of fusion of crystal) x 100
The measured value of the heat of fusion of PA6 was 60.9 mJ / mg. According to the data of TA Instrument, the heat of fusion of 100% crystal of PA6 is 230 mJ / mg. _{The crystallinity X c} obtained using these was 26.5%.

When the coefficient of linear expansion of PA6 was calculated using the numerical values of these parameters, a value close to the actually measured value was obtained as shown in FIG. Curve in FIG. 10, the angle phi _t of tie molecules indicates the calculated values of the linear expansion coefficient of PA6 in the range of 30 degrees or less. The circles in FIG. 10 indicate the measured values of the coefficient of linear expansion of the fiber material of PA6. From this result, it can be said that the unit structure 20A of the polyamide-based fiber material is highly likely to be correct.

Next, a method for producing the fiber material of PA12 of the present embodiment will be described. As shown in FIG. 11, the method for producing the fiber material of PA12 includes a spinning step S1 and a drawing step S2.

In the spinning step S1, as shown in FIG. 12, pellets of the polyamide 12 are introduced into the extruder 31. Inside the extruder 31, the pellet is heated above its melting point. The heated and melted material is extruded through a nozzle to be fibrous, and then cooled by the coolant in the cooling tank 32 to be solidified. In this way, unstretched fibers of the polyamide 12 are formed by melt spinning.

Subsequently, in the stretching step S2, as shown in FIG. 12, the unstretched fiber is stretched by a roller 34 or the like while being heated by the heater 33 at an appropriate temperature below the melting point (for example, around 100 ° C.). .. By appropriately setting the heating conditions and the speed of the roller 34, the stretching ratio with respect to the unstretched state at this time is set to, for example, 3 times, 4 times, or 5 times. By this stretching step, anisotropy is given to each shape of the plurality of accommodating portions 24. The longitudinal direction of each of the plurality of accommodating portions 24 is a direction along the fiber axial direction D1.

In this way, the fiber material of PA12 in a stretched state is produced. That is, the unit structure 20A is obtained by performing the spinning step S1 and the drawing step S2. When the drawing step S2 is not performed, the unstretched fiber may not have the unit structure 20A shown in FIG.

Next, the experimental results comparing the fiber material of PA12 in the stretched state with the fiber materials of PA6, PA66, and PA610 in the stretched state will be described. As described in Patent Document 1, there is a conventional actuator made of each fiber material of PA6 and PA66. Therefore, the fiber materials of PA6 and PA66 used here correspond to conventional actuators.

The fiber material of PA12, the fiber material of PA6, and the fiber material of PA66 were produced by the above-mentioned production method. The spinning temperature of PA12 is 210 ° C. The spinning temperature of PA6 is 260 ° C. The spinning temperature of PA66 is 285 ° C. The maximum draw ratio of each of PA6 and PA66 was 4 times. Therefore, the fiber materials of PA12, PA6, and PA66 were produced by setting the draw ratio to the same 4 times. Then, the shrinkage rate of each of the produced fiber materials was measured. In the measurement of the shrinkage rate, the shrinkage rate of each sample was measured when the temperature of each sample was raised from 30 ° C. to 150 ° C. without applying tension to each sample. The measurement result is shown in FIG.

FIG. 13 shows the relationship between the shrinkage rate of each fiber material and the material density. This material density is the true density. The material density of each fiber material is a value measured by the measuring method specified in JIS K 7112. The straight line in FIG. 13 is the prediction result of the shrinkage rate by the theoretical model. The Young's modulus of each of the fiber materials of PA12, PA6, and PA66 is close to each other.

According to the theoretical model of the unit structure 20A described above, as can be seen from the equation of Equation 1, the amount of shrinkage of the fiber material is proportional to the _{coefficient of linear expansion α a of the amorphous portion 23.} That is, the larger the coefficient of linear expansion of the amorphous portion 23, the larger the amount of shrinkage of the fiber material. Further, the expansion of the amorphous portion 23 is due to the expansion of the free volume. Therefore, the coefficient of linear expansion α _a of the amorphous portion 23 correlates with the material density of the amorphous portion 23. That is, the smaller the material density of the amorphous portion 23, the larger the coefficient of linear expansion of the amorphous portion 23. Therefore, the amount of fiber shrinkage can be increased by using a material having a low material density in the amorphous portion 23. In general, in a polyamide-based fiber material, the ratio of the amorphous portion 23 to the entire material is larger than the ratio of the crystalline portion 21 to the entire material. Therefore, there is a correlation between the material density of the amorphous portion 23 and the material density of the entire material. Therefore, the amount of fiber shrinkage can be increased by using a fiber material having a low material density.

From the measurement results of FIG. 13, it can be seen that, according to the above theory, the fiber material of PA12 having a material density smaller than that of PA6 and PA66 exhibits a larger shrinkage rate than the fiber material of PA6 and PA66, respectively. Therefore, as shown by the straight line in FIG. 13, it can be seen that the lower the material density of the fiber material, the larger the shrinkage rate of the fiber material.

Further, as described in Non-Patent Document 1 described above, there is a conventional actuator made of a fiber material of PA11. The material density of PA11 is 1.03 g / cm ³ .
The material density of PA12 is 1.01 g / cm ³ , which is smaller than the material density of PA11. As described above, the lower the material density of the fiber material, the larger the shrinkage rate of the fiber material. Therefore, it is estimated that the fiber material of PA12 exhibits a larger shrinkage rate than the fiber material of PA11. ..

Therefore, it is preferable that the actuator 1 is made of the fiber material of PA12. When the actuator 1 is composed of the fiber material of PA12, the fiber material of PA12 may or may not contain another material.

In the above-described embodiment, the fiber material of PA12 has been described as a material that embodies the above-mentioned material design. However, the material that embodies the above-mentioned material design may be a fiber material composed of a polyamide resin other than PA12. The polyamide resin is a synthetic resin having an amide bond. As described above, as shown by the straight line in FIG. 13, it has been found by the present inventor that the lower the material density of the fiber material, the larger the shrinkage rate of the fiber material. Therefore, the fiber material made of a polyamide resin other than PA12 may have a lower material density than the fiber material of the polyamide resin used in conventional actuators. Comparing the material densities of PA6, PA66 and PA11, the material density of PA11 is the lowest. Therefore, the fiber material constituting the actuator 1 may be a polyamide resin ^{fiber material having a density of more than 0 g / cm 3 and} less than 1.03 g / cm ^3. According to this, it is possible to increase the output as compared with the conventional actuator made of the fiber materials of PA6, PA66, and PA11.

Further, the fiber material constituting the actuator 1 is not limited to the case where it is composed of a single material of polyamide resin. The fiber material constituting the actuator 1 may be composed of a polymer material containing a polyamide resin and another polymer material. In short, the fiber material constituting the actuator 1 may be made of a polymer material containing a polyamide resin. When the fiber material constituting the actuator 1 is composed of a polymer material containing a polyamide resin and another polymer material, the density of the polymer material having the unit structure 20A shown in FIG. 4 is within the above range. It suffices if it meets.

At the time of filing, polymethylpentene is known as a thermoplastic resin having the lowest material density. The density of polymethylpentene is 0.83 g / cm ³ . Therefore, a polymer material having a small material density such as polymethylpentene may be mixed with the polyamide resin to obtain a desired density of the polymer material having the unit structure 20A shown in FIG. In this case, the material density of the mixed polymer material is greater than ^{0.83 g / cm 3.} Considering that the minimum density of the polymer material existing at the time of filing is 0.83 g / cm ^3, it is manufactured when the fiber material constituting the actuator 1 is composed of a single polyamide resin material. The material density of the fiber material is assumed to be greater than ^{0.83 g / cm 3.}

Further, as shown by the straight line in FIG. 13, the fiber material composed of the polymer material having the unit structure 20A shown in FIG. 4, which is a polymer material other than the polyamide resin, shrinks as the material density decreases. It is considered that there is a relationship that the rate increases. Therefore, the fiber material constituting the actuator 1 may be at least composed of a thermoplastic crystalline or semi-crystalline polymer material other than the polyamide resin as long as it has the unit structure 20A shown in FIG. .. The crystalline or semi-crystalline polymer material is a polymer material having a crystalline portion. Further, the fiber material constituting the actuator 1 may include a material other than the polymer material. Further, the shape of the material embodying the above-mentioned material design does not have to be a fiber, and may be a shape other than a fiber such as a film.

(Second Embodiment)
FIG. 14A is a side view of the actuator 1A of the present embodiment before heating. 14 (b) is a top view of the actuator 1A of FIG. 14 (a). FIG. 14C is a side view of the actuator 1A of the present embodiment after heating.

As shown in FIGS. 14A, 14B, and 14C, the actuator 1A of the present embodiment has a fiber shape. That is, the actuator 1A is made of a fiber material and contracts in the fiber axial direction D11 of the fiber material by inputting thermal energy as external energy. As a result, the tensile force in the fiber axial direction D11 is output to the outside.

The fiber material constituting the actuator 1A includes a braided sleeve 42, a polymer material 43, and a knot portion 44. The braided sleeve 42 corresponds to the skeletal structure portion 12 in FIG. The polymer material 43 corresponds to the volume change portion 13 in FIG.

The braided sleeve 42 has a tubular structure in which one or more fibers are combined to surround the accommodating portion 41, and has a structure that is more easily expanded and contracted in the width direction D12 orthogonal to the fiber axial direction D11 than in the fiber axial direction D11. I'm doing it. In the cylindrical braided sleeve 42, the width direction D12 is the radial direction of the braided sleeve 42. The accommodating portion 41 of the braided sleeve 42 corresponds to the accommodating portion 11 of the skeletal structure portion 12. As shown in FIGS. 14A and 14B, the braided sleeve 42 has a cylindrical shape, but it does not have to be cylindrical. Examples of the fibers constituting the braided sleeve 42 include carbon fibers, metal fibers, glass fibers, ceramic fibers, and polymer fibers.

More specifically, the braided sleeve 42 has a structure in which a plurality of fibers 421 extending along the fiber axial direction D11 are bundled with a gap from each other. The distance between the fibers of the plurality of fibers 421 may be such that the polymer material 43 contained therein does not flow out from the braided sleeve 42. At both ends of each of the plurality of fibers 421, each of the plurality of fibers 421 and the polymer material 43 are fixed by the fixing member 45.

Even if a tensile stress in the fiber axial direction D11 is applied to the braided sleeve 42, the plurality of fibers 421 constituting the braided sleeve 42 do not stretch or are difficult to stretch. Further, when a tensile stress in the width direction D12 is applied to the braided sleeve 42, the plurality of fibers 421 constituting the braided sleeve 42 are bent. As a result, a structure that expands and contracts more easily in the width direction D12 than in the fiber axis direction D11 is realized. The braided sleeve 42 preferably has a structure that does not extend in the fiber axis direction D11 with respect to the basic shape shown in FIG. 14B and extends in the width direction D12 with respect to the basic shape.

The braided sleeve 42 may have other configurations. For example, the braided sleeve 42 may be one in which a plurality of fibers are combined and knitted in a net shape. Further, the braided sleeve 42 may be one in which one fiber is woven in a mesh pattern. In the case of a net-like knitted structure, the braided sleeve 42 has a gap. The size of the gap may be such that the polymer material 43 contained therein does not flow out from the braided sleeve 42. Further, the braided sleeve 42 does not have to be knitted in a net shape as long as it has a structure that easily expands and contracts in the width direction D12 rather than the fiber axis direction D11.

The polymer material 43 is housed in the internal space of the braided sleeve 42. The polymer material 43 is a solid that expands isotropically by inputting thermal energy when its outer shape is not restricted. When the thermal energy input conditions are the same, the volume increase of the polymer material 43 is larger than the volume increase of the fibers constituting the braided sleeve 42. That is, the polymer material 43 is a material having a larger expansion coefficient than the fibers constituting the braided sleeve 42.

As the polymer material 43, an elastomer (that is, a polymer material having elasticity) is used. Elastomers include rubber and thermoplastic elastomers. Examples of the rubber include silicon rubber (for example, PDMS), natural rubber, urethane rubber, acrylic rubber, fluororubber, NBR and the like. Examples of the thermoplastic elastomer include paraffin and EVA.

The knot 44 suppresses the expansion of the braided sleeve 42 in the width direction D12. The knot portion 44 has a shape thinner than the outer shape of the braided sleeve 42, and is a thread-shaped member. The knots 44 are annularly or spirally secured around the braided sleeve 42 at predetermined intervals.

For example, the node 44 is composed of a plurality of annular portions as shown in FIG. 14 (a). Each of the plurality of annular portions circulates around the braided sleeve 42, and is arranged so as to be spaced apart from each other in the fiber axial direction D11. Alternatively, the knot portion 44 may have a configuration in which a single thread-shaped member is spirally wound around the braided sleeve 42 at predetermined intervals.

Examples of the material constituting the knot portion 44 include carbon fiber, metal fiber, glass fiber, ceramic fiber, polymer fiber and the like. The material constituting the knot portion 44 may be one or a plurality of materials.

In the actuator 1A of the present embodiment, the Young's modulus of the fibers constituting the braided sleeve 42 is higher than the Young's modulus of the polymer material 43. Therefore, the Young's modulus of the braided sleeve 42 is higher than the Young's modulus of the polymer material 43.

Further, in the actuator 1A of the present embodiment, the volume of the polymer material 43 is increased by heating the actuator 1A and inputting heat energy to the polymer material 43. At this time, as the volume of the polymer material 43 increases, the braided sleeve 42 expands in the width direction D12 and the braided sleeve 42 contracts in the fiber axial direction D11, as can be seen by comparing FIGS. 14 (a) and 14 (c). do. That is, the braided sleeve 42 is deformed so that the accommodating portion 41 contracts in the fiber axis direction D11 and the accommodating portion 41 expands in the width direction D12. In the present embodiment, the direction along the fiber axial direction D11 corresponds to one direction. The width direction D12 corresponds to another direction different from one direction.

As a result, as compared with the case where the actuator 1A is composed of only the materials constituting the braided sleeve 42 and the case where the actuator 1A is composed of only the polymer material 43, the actuator 1A generated when thermal energy is input The strain can be increased.

As described above, also in the present embodiment, it is possible to give the actuator 1A both a property that the strain generated by the input of external energy is large and a property that the Young's modulus is high. Therefore, the output of the actuator 1A can be increased.

As shown in FIGS. 15A, 15B, and 15C, the fiber material constituting the actuator 1A of the present embodiment may not include the knot 44. Even if the node 44 is not included, the output of the actuator 1A can be increased for the above reason. Note that FIG. 15A is a side view of the actuator 1A having no knots of the present embodiment before heating. FIG. 15B is a top view of the actuator 1A of FIG. 15A. FIG. 15C is a side view of the actuator 1A having no knots of the present embodiment after heating.

Further, according to the actuator 1A of the present embodiment, the following effects are obtained. The fibrous material constituting the actuator 1A includes a knot 44. As shown in FIG. 16, the shrinkage rate of the actuator 1A in the fiber axial direction D11 when the expansion rate of the polymer material 43 is the same in the case where the knot portion 44 is present is compared with the case where the knot portion 44 is not present. Can be increased. That is, it is possible to increase the amount of contraction of the actuator 1A in the fiber axis direction D11 when the amount of volume change of the polymer material 43 is the same. The amount of contraction of the actuator 1A can be adjusted by changing the distance between adjacent knots 44 in the fiber axis direction D11.

Further, in the actuator 1A of the present embodiment, it is preferable that the fibers constituting the braided sleeve 42 have conductivity like carbon fibers, metal fibers and the like, and generate heat when energized. According to this, heat energy can be input to the polymer material 43 by energizing the braided sleeve 42.

Similarly, in the actuator 1A of the present embodiment, it is preferable that the material constituting the node 44 has conductivity and generates heat when energized, such as carbon fiber and metal fiber. According to this, heat energy can be input to the polymer material 43 by energizing the node 44.

Next, an embodiment of the actuator 1A having the above structure will be described. The present inventor produced the actuator 1A having the structure shown in FIG. 20 by the procedure shown in FIGS. 17, 18, and 19.

As shown in FIG. 17, a carbon fiber braided sleeve 42a as the braided sleeve 42 and a silicon rubber cord 43a as the polymer material 43 were prepared, and the silicon rubber cord 43a was put in the carbon fiber braided sleeve 42a. In the carbon fiber braided sleeve 42a, the plurality of fibers 421 constituting the braided sleeve 42 are carbon fibers. In the carbon fiber braided sleeve 42a, a plurality of fibers 421 are combined and knitted in a net shape. In FIG. 17, a large void is formed between each of the plurality of fibers 421, but in reality, a void having a size that can be visually recognized is not formed. The prepared carbon fiber braided sleeve 42a has a minimum inner diameter of 5 mm and a maximum inner diameter of 8 mm. The prepared silicone rubber cord 43a is a round cord having a diameter of 5 mm and a hardness of 50, which is made of silicone rubber.

Subsequently, as shown in FIG. 18, in order to suppress the axial expansion of the silicone rubber cord 43a, the axial end of the carbon fiber braided sleeve 42a and the axial end of the silicone rubber cord 43a are fixed. It was fixed with an epoxy adhesive 45a as a member 45.

Subsequently, as shown in FIG. 19, a wire 44a was prepared, and the wire 44a was spirally wound around the carbon fiber braided sleeve 42a. Further, the wire 44a was fixed to the carbon fiber braided sleeve 42a with an epoxy adhesive. As a result, the node 44 was formed. As the wire 44a, a nichrome wire having a diameter of 0.6 mm was used.

In this way, the actuator 1A having the structure shown in FIG. 20 was manufactured. In the manufactured actuator 1A, the silicon rubber cord 43a is arranged inside the carbon fiber braided sleeve 42a. Further, a spiral knot is formed by the wire 44a.

When the produced actuator 1A was heated at 200 ° C., as shown in FIG. 21, the actuator 1A expanded in the width direction D12 and the actuator 1A contracted in the fiber axial direction D11. At this time, the present inventor confirmed that the produced actuator 1A generates a stress of 5 times or more as compared with the actuator disclosed in the following document in which PA6 is used.
CS Haines et al., Artificial muscles from fishing line and sewing thread. Science 343, 868-872 (2014)

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be appropriately modified within the scope of claims, and includes various modifications and modifications within an equal range. Further, the above-described embodiments are not unrelated to each other, and can be appropriately combined unless the combination is clearly impossible. Further, in each of the above embodiments, it goes without saying that the elements constituting the embodiment are not necessarily essential except when it is clearly stated that they are essential and when they are clearly considered to be essential in principle. stomach. Further, in each of the above embodiments, when numerical values such as the number, numerical values, quantities, and ranges of the constituent elements of the embodiment are mentioned, when it is clearly stated that they are particularly essential, and in principle, the number is clearly limited to a specific number. It is not limited to the specific number except when it is done. Further, in each of the above embodiments, when referring to the material, shape, positional relationship, etc. of the constituent elements, etc., except when specifically specified or when the material, shape, positional relationship, etc. are limited to a specific material, shape, positional relationship, etc. in principle. , The material, shape, positional relationship, etc. are not limited.

10 Unit structure 11 Storage part 12 Skeletal structure part 13 Volume change part 21 Multiple crystal parts 22 Multiple tie molecules 23 Multiple non-competition 42 Braided sleeve 43 Polymer material

Claims (11)

It ’s an actuator,
The skeletal structure (12, 21, 22, 42) forming the skeletal structure surrounding the housing (11, 24, 41),
It has a volume changing portion (13, 23, 43) accommodated in the accommodating portion, and has a volume changing portion (13, 23, 43).
The volume of the volume change portion is increased by inputting external energy other than mechanical energy from the outside.
The skeletal structure portion has a higher Young's modulus than the volume change portion.
When the external energy is input to the volume change portion, the volume of the volume change portion is increased, and the volume of the volume change portion is increased, so that the accommodating portion contracts in one direction (D2, D11). An actuator in which the skeleton structure portion is deformed so that the accommodating portion expands in another direction (D3, D12) different from the one direction. The actuator is made of a fiber material, and when the external energy is input, the tensile force in the fiber axial direction (D1, D11) of the fiber material is output.
The actuator according to claim 1, wherein the one direction is a direction along the fiber axis direction. The shape of the accommodating portion is an anisotropic shape in which the maximum width (LD2) of the accommodating portion in one direction is longer than the maximum width (LD3) of the accommodating portion in the other direction. 2. The actuator according to 2. In the fiber material, a plurality of crystal portions (21) in which polymer chains are regularly arranged and a plurality of tie molecules (22) in which polymer chains extend so as to connect each of the plurality of crystal portions to each other. And at least composed of a polymer material having a plurality of amorphous portions (23) in which polymer chains are irregularly arranged.
The plurality of tie molecules include a plurality of first tie molecules (221) extending in the first direction (D2), which is one direction, and a plurality of second tie molecules (222) extending in the first direction. Including
Each of the plurality of first tie molecules and each of the plurality of second tie molecules are alternately provided in a second direction orthogonal to the first direction.
Next to one of the second tie molecules of the plurality of second tie molecules and one side of the second direction with respect to the one second tie molecule of the plurality of first tie molecules. A first space (B1) is formed between the first tie molecule (221a) and the one located.
The one second tie molecule and one first tie molecule located next to the other side in the second direction with respect to the one second tie molecule among the plurality of first tie molecules ( A second space (B2) is formed between the 221b) and the space (B2).
The plurality of crystal portions include a plurality of first crystal portions (21a) provided in the first space and a plurality of second crystal portions (21b) provided in the second space.
The plurality of amorphous portions include a plurality of first amorphous portions (23a) provided in the first space and a plurality of second amorphous portions (23b) provided in the second space.
In the first space, each of the plurality of first crystal portions and each of the plurality of first amorphous portions are alternately provided in the first direction.
In the second space, each of the plurality of second crystal portions and each of the plurality of second amorphous portions are alternately provided in the first direction.
The first crystal portion of the plurality of first crystal portions in the first space is the first crystal portion with respect to the second amorphous portion of the plurality of second amorphous portions in the second space. Along with facing each other in two directions, the second crystal portion of one of the plurality of second crystal portions in the second space is the first amorphous portion of the plurality of first amorphous portions of the first space. Facing the unit in the second direction,
The length of each of the plurality of amorphous portions in the first direction is longer than the length of each of the plurality of crystal portions in the first direction.
The volume change portion is an amorphous portion of one of the plurality of amorphous portions.
The skeletal structure portion is a portion surrounding the one amorphous portion of the plurality of crystal portions and the plurality of tie molecules.
The density of the polymeric material is greater than ^{0g / cm 3, 1.03g / cm} 3 less than actuator according to claim 3. The actuator according to claim 4, wherein the polymer material contains a resin having an amide bond. The actuator according to claim 5, wherein the resin is polyamide 12. An actuator composed of a fiber material and outputting a tensile force in the fiber axis direction (D1) of the fiber material by inputting external energy other than mechanical energy.
An actuator in which the fiber material is at least composed of a polymer material containing polyamide 12. The skeletal structure portion is formed by combining one or more fibers to form a tubular structure surrounding the accommodating portion, and expands and contracts in the width direction (D12) orthogonal to the fiber axis direction rather than the fiber axis direction. A braided sleeve (42) with an easy structure,
The volume change portion is a solid polymer material (43) that expands isotropically by inputting thermal energy as the external energy when there is no restriction on the outer shape.
When the thermal energy is input to the polymer material, the volume of the polymer material increases, and when the volume of the volume changing portion increases, the accommodating portion contracts in the fiber axis direction, and the accommodating portion shrinks. The actuator according to claim 2, wherein the braided sleeve is deformed so that the portion expands in the width direction. The actuator according to claim 8, wherein the one or more fibers constituting the braided sleeve generate heat when energized. The fibrous material has a knot (44) that suppresses the expansion of the braided sleeve in the width direction.
The actuator according to claim 9, wherein the knots have a shape thinner than the outer shape of the braided sleeve and are fixed around the braided sleeve in an annular shape or a spiral shape at predetermined intervals. The actuator according to claim 10, wherein the material constituting the node generates heat when energized.

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